1. Field of the Invention
The subject invention relates to a barrel in an extruding assembly of the type for the continuous blending and plasticizing of a heat softenable and curable molding compound and, more specifically, to a particular arrangement for venting gases.
2. Description of the Prior Art
Assemblies for extruding plastic are well known and frequently include a main extruder unit and a feed extruder unit in series to feed material to the main extruder. Each unit has a pair of screws independently driven for varying rotational speeds. The main extruder unit includes a back vented barrel having top, bottom, front, back and first and second side surfaces. A main extruder passage extends between the front and back surfaces, a feed extruder passage extends from the first side surface and into the main extruder passage, and a vent passage extends from the main extruder passage and is spaced from and between the feed extruder passage and the back surface. An example of such an assembly is disclosed in U.S. Pat. Nos. 4,063,718 to Koch and 4,134,714 to Driskill. As the background in each of these patents relates, the relative placement between the various passages can be critical to maximizing the performance of the assembly. In addition, it is important that the assembly have versatility for processing various different materials.